UnratedFix available
net: sched: act_csum: validate nested VLAN headers
Type: advisorySources: OSV
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.258, 5.15.209, 6.1.175, 6.12.83, 6.18.24, 6.19.14, 6.6.136
- CVEs
- CVE-2026-31684
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 07:05 UTC · Revision 1
Source evidence
net: sched: act_csum: validate nested VLAN headers
core-osv · Original sourcePublished 25 Apr 2026, 08:47 UTC
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_csum: validate nested VLAN headers tcf_csum_act() walks nested VLAN headers directly from skb->data when an skb still carries in-payload VLAN tags. The current code reads vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without first ensuring that the full VLAN header is present in the linear area. If only part of an inner VLAN header is linearized, accessing h_vlan_encapsulated_proto reads past the linear area, and the following skb_pull(VLAN_HLEN) may violate skb invariants. Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and pulling each nested VLAN header. If the header still is not fully available, drop the packet through the existing error path.
osv:CVE-2026-31684
Kernel
Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83, 6.18.24, 6.19.14
Complete source record
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